Hey Nfri, I don't go with your idea that we dream all through the night. There are clearly very different levels of activity that can be measured in the sleeping brain, and the slow wave Delta activity really does seem to be that the brain is working at a much slower pace than when in REM.
No one quite understands why we dream, but the chemical cycles strongly suggest heightened consciousness during dreams.

I don't quite get the point about memory either. Our life experience memories don't disappear when we sleep. They are still there, and it is the block on recall of those memories that stops or hinders lucid dreaming.
We should redefine consciousness to include dreaming as an inner consciousness, and waking life as external consciousness perhaps?